The　structure　and　properties　of　Ca/Zr　doped　cubic　BaTiO3　ceramics　have　been　studied　using　the　first　principles　in　which　chemical　elements　of　Ca　or　Zr　have　been　partially　and　uniformly　substituted　by　Ba　or　Ti　sites.　The　calculated　results　show　that　the　doping　of　CaZrO3　and　the　Fermi　surface　transfers　to　the　valence　band　increases　the　energy　band　difference.　An　important　contribution　to　the　total　state　density　of　the　Ca/Zr-doped　BaTiO3　system　is　the　4d　orbital　of　Zr　atoms,　and　a　strong　Orbital　hybridization　is　caused　by　the　p-d　interaction　near　the　Fermi　level　introduced　by　Ca/Zr　doping.　The　refractive　index　(n)　for　a　pure　system　is　2.525　and　1.617　for　a　doped　system.　The　doping　of　CaZrO3　makes　it　less　complicated　for　BaTiO3　to　tetragonal　phase　after　Ca/Zr　doping,　which　improves　the　overall　performance　of　BaTiO3.